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1 | # IO::Pipe.pm |
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2 | # |
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3 | # Copyright (c) 1996 Graham Barr <Graham.Barr@tiuk.ti.com>. All rights |
4 | # reserved. This program is free software; you can redistribute it and/or |
5 | # modify it under the same terms as Perl itself. |
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6 | |
7 | package IO::Pipe; |
8 | |
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9 | require 5.000; |
10 | |
11 | use IO::Handle; |
12 | use strict; |
13 | use vars qw($VERSION); |
14 | use Carp; |
15 | use Symbol; |
16 | |
17 | $VERSION = "1.09"; |
18 | |
19 | sub new { |
20 | my $type = shift; |
21 | my $class = ref($type) || $type || "IO::Pipe"; |
22 | @_ == 0 || @_ == 2 or croak "usage: new $class [READFH, WRITEFH]"; |
23 | |
24 | my $me = bless gensym(), $class; |
25 | |
26 | my($readfh,$writefh) = @_ ? @_ : $me->handles; |
27 | |
28 | pipe($readfh, $writefh) |
29 | or return undef; |
30 | |
31 | @{*$me} = ($readfh, $writefh); |
32 | |
33 | $me; |
34 | } |
35 | |
36 | sub handles { |
37 | @_ == 1 or croak 'usage: $pipe->handles()'; |
38 | (IO::Pipe::End->new(), IO::Pipe::End->new()); |
39 | } |
40 | |
41 | my $do_spawn = $^O eq 'os2'; |
42 | |
43 | sub _doit { |
44 | my $me = shift; |
45 | my $rw = shift; |
46 | |
47 | my $pid = $do_spawn ? 0 : fork(); |
48 | |
49 | if($pid) { # Parent |
50 | return $pid; |
51 | } |
52 | elsif(defined $pid) { # Child or spawn |
53 | my $fh; |
54 | my $io = $rw ? \*STDIN : \*STDOUT; |
55 | my ($mode, $save) = $rw ? "r" : "w"; |
56 | if ($do_spawn) { |
57 | require Fcntl; |
58 | $save = IO::Handle->new_from_fd($io, $mode); |
59 | # Close in child: |
60 | fcntl(shift, Fcntl::F_SETFD(), 1) or croak "fcntl: $!"; |
61 | $fh = $rw ? ${*$me}[0] : ${*$me}[1]; |
62 | } else { |
63 | shift; |
64 | $fh = $rw ? $me->reader() : $me->writer(); # close the other end |
65 | } |
66 | bless $io, "IO::Handle"; |
67 | $io->fdopen($fh, $mode); |
68 | |
69 | if ($do_spawn) { |
70 | $pid = eval { system 1, @_ }; # 1 == P_NOWAIT |
71 | my $err = $!; |
72 | |
73 | $io->fdopen($save, $mode); |
74 | $save->close or croak "Cannot close $!"; |
75 | croak "IO::Pipe: Cannot spawn-NOWAIT: $err" if not $pid or $pid < 0; |
76 | return $pid; |
77 | } else { |
78 | exec @_ or |
79 | croak "IO::Pipe: Cannot exec: $!"; |
80 | } |
81 | } |
82 | else { |
83 | croak "IO::Pipe: Cannot fork: $!"; |
84 | } |
85 | |
86 | # NOT Reached |
87 | } |
88 | |
89 | sub reader { |
90 | @_ >= 1 or croak 'usage: $pipe->reader()'; |
91 | my $me = shift; |
92 | my $fh = ${*$me}[0]; |
93 | my $pid = $me->_doit(0, $fh, @_) |
94 | if(@_); |
95 | |
96 | close ${*$me}[1]; |
97 | bless $me, ref($fh); |
98 | *{*$me} = *{*$fh}; # Alias self to handle |
99 | bless $fh; # Really wan't un-bless here |
100 | ${*$me}{'io_pipe_pid'} = $pid |
101 | if defined $pid; |
102 | |
103 | $me; |
104 | } |
105 | |
106 | sub writer { |
107 | @_ >= 1 or croak 'usage: $pipe->writer()'; |
108 | my $me = shift; |
109 | my $fh = ${*$me}[1]; |
110 | my $pid = $me->_doit(1, $fh, @_) |
111 | if(@_); |
112 | |
113 | close ${*$me}[0]; |
114 | bless $me, ref($fh); |
115 | *{*$me} = *{*$fh}; # Alias self to handle |
116 | bless $fh; # Really wan't un-bless here |
117 | ${*$me}{'io_pipe_pid'} = $pid |
118 | if defined $pid; |
119 | |
120 | $me; |
121 | } |
122 | |
123 | package IO::Pipe::End; |
124 | |
125 | use vars qw(@ISA); |
126 | |
127 | @ISA = qw(IO::Handle); |
128 | |
129 | sub close { |
130 | my $fh = shift; |
131 | my $r = $fh->SUPER::close(@_); |
132 | |
133 | waitpid(${*$fh}{'io_pipe_pid'},0) |
134 | if(defined ${*$fh}{'io_pipe_pid'}); |
135 | |
136 | $r; |
137 | } |
138 | |
139 | 1; |
140 | |
141 | __END__ |
142 | |
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143 | =head1 NAME |
144 | |
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145 | IO::pipe - supply object methods for pipes |
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146 | |
147 | =head1 SYNOPSIS |
148 | |
149 | use IO::Pipe; |
150 | |
151 | $pipe = new IO::Pipe; |
152 | |
153 | if($pid = fork()) { # Parent |
154 | $pipe->reader(); |
155 | |
156 | while(<$pipe> { |
157 | .... |
158 | } |
159 | |
160 | } |
161 | elsif(defined $pid) { # Child |
162 | $pipe->writer(); |
163 | |
164 | print $pipe .... |
165 | } |
166 | |
167 | or |
168 | |
169 | $pipe = new IO::Pipe; |
170 | |
171 | $pipe->reader(qw(ls -l)); |
172 | |
173 | while(<$pipe>) { |
174 | .... |
175 | } |
176 | |
177 | =head1 DESCRIPTION |
178 | |
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179 | C<IO::Pipe> provides an interface to createing pipes between |
180 | processes. |
181 | |
182 | =head1 CONSTRCUTOR |
183 | |
184 | =over 4 |
185 | |
186 | =item new ( [READER, WRITER] ) |
187 | |
188 | Creates a C<IO::Pipe>, which is a reference to a |
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189 | newly created symbol (see the C<Symbol> package). C<IO::Pipe::new> |
190 | optionally takes two arguments, which should be objects blessed into |
191 | C<IO::Handle>, or a subclass thereof. These two objects will be used |
192 | for the system call to C<pipe>. If no arguments are given then then |
193 | method C<handles> is called on the new C<IO::Pipe> object. |
194 | |
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195 | These two handles are held in the array part of the GLOB until either |
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196 | C<reader> or C<writer> is called. |
197 | |
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198 | =back |
199 | |
200 | =head1 METHODS |
201 | |
202 | =over 4 |
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203 | |
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204 | =item reader ([ARGS]) |
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205 | |
206 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a |
207 | handle at the reading end of the pipe. If C<ARGS> are given then C<fork> |
208 | is called and C<ARGS> are passed to exec. |
209 | |
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210 | =item writer ([ARGS]) |
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211 | |
212 | The object is re-blessed into a sub-class of C<IO::Handle>, and becomes a |
213 | handle at the writing end of the pipe. If C<ARGS> are given then C<fork> |
214 | is called and C<ARGS> are passed to exec. |
215 | |
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216 | =item handles () |
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217 | |
218 | This method is called during construction by C<IO::Pipe::new> |
219 | on the newly created C<IO::Pipe> object. It returns an array of two objects |
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220 | blessed into C<IO::Pipe::End>, or a subclass thereof. |
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221 | |
222 | =back |
223 | |
224 | =head1 SEE ALSO |
225 | |
226 | L<IO::Handle> |
227 | |
228 | =head1 AUTHOR |
229 | |
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230 | Graham Barr <bodg@tiuk.ti.com> |
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231 | |
232 | =head1 COPYRIGHT |
233 | |
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234 | Copyright (c) 1996 Graham Barr. All rights reserved. This program is free |
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235 | software; you can redistribute it and/or modify it under the same terms |
236 | as Perl itself. |
237 | |
238 | =cut |